In storage bins for fluent material, it is often desirable or necessary to provide air tight seals at the input and discharge openings of such storage bins. For example, immediately following the manufacture of asphalt aggregate material used for paving, the material is typically placed in large storage bins known as surge bins, from which the material can be dispersed into trucks to be transported from the manufacturing plant to the job site where the material will be used. It is well known that hot asphalt aggregate mix oxidizes and deteriorates when exposed to the air, and therefore storage bins for asphalt aggregate material are provided with air tight openings and are often filled with an inert atmosphere.
In the prior art, sealing means have been provided in connection with gate apparatus to close the input and discharge openings of storage bins. Such sealing means have included conventional gaskets, inflatable gaskets, and liquid sealing means. An apparatus including a discharge gate capable of providing a liquid seal is shown in U.S. Pat. No. 3,949,907. None of such prior art devices have provided a liquid seal for the input opening in the top of a storage bin.